"There are few things in the enthusiast computing world that are as misunderstood and feared as water cooling. When done right, it can be a beautiful addition to a case while keeping temperatures down and noise low. When done poorly, it can be a tangled mess of dangerous tubing that cools worse than air, but can fry your new £350 graphics card in a moment.
It's the fear of that latter scenario which has left many of us on our safe, air-cooled ground. After all, investing in water cooling is not cheap to begin with, and when added to the risks, it almost seems like a no-brainer to go buy the latest block of Zalman copper and call it a day.
Some people wouldn't even know where to begin when setting up a system. Yeah, there are basic parts, but which ones? Is it best to stick with a brand name? Is there a certain size to buy? And how can the system stay safe if there's a leak?"

FULL STORY @ BIT-TECH(http://www.bit-tech.net/hardware/2007/08/22/watercooling_101/1)